The selectivity behavior of zeolite-modified electrodes (ZMEs) fabricated by electrophoretic deposition (EPD) was investigated using cyclic voltammetry in an aqueous KCl solution containing Pb and Cd as probe ions. The ZME of zeolite Y coated with Nafion was found to exhibit a high level of selectivity for Pb over Cd, with a selectivity coefficient of 0.068. The Pb/Cd selectivity of the EPD-ZME was then studied as a function of type of zeolite, cation of the supporting electrolyte, anion of the supporting electrolyte and metallic salts, and thickness of the zeolite and Nafion layers. All of the factors, except layer thickness, was found to have a significant effect on the selectivity behavior of the ZME.